Java tutorial
/* * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER. * * Copyright (c) 1997-2017 Oracle and/or its affiliates. All rights reserved. * * The contents of this file are subject to the terms of either the GNU * General Public License Version 2 only ("GPL") or the Common Development * and Distribution License("CDDL") (collectively, the "License"). You * may not use this file except in compliance with the License. You can * obtain a copy of the License at * https://oss.oracle.com/licenses/CDDL+GPL-1.1 * or LICENSE.txt. See the License for the specific * language governing permissions and limitations under the License. * * When distributing the software, include this License Header Notice in each * file and include the License file at LICENSE.txt. * * GPL Classpath Exception: * Oracle designates this particular file as subject to the "Classpath" * exception as provided by Oracle in the GPL Version 2 section of the License * file that accompanied this code. * * Modifications: * If applicable, add the following below the License Header, with the fields * enclosed by brackets [] replaced by your own identifying information: * "Portions Copyright [year] [name of copyright owner]" * * Contributor(s): * If you wish your version of this file to be governed by only the CDDL or * only the GPL Version 2, indicate your decision by adding "[Contributor] * elects to include this software in this distribution under the [CDDL or GPL * Version 2] license." If you don't indicate a single choice of license, a * recipient has the option to distribute your version of this file under * either the CDDL, the GPL Version 2 or to extend the choice of license to * its licensees as provided above. However, if you add GPL Version 2 code * and therefore, elected the GPL Version 2 license, then the option applies * only if the new code is made subject to such option by the copyright * holder. */ package javax.mail.event; import java.util.*; import javax.mail.*; /** * This class notifies changes in the number of messages in a folder. <p> * * Note that some folder types may only deliver MessageCountEvents at * certain times or after certain operations. IMAP in particular will * only notify the client of MessageCountEvents when a client issues a * new command. Refer to * <A HREF="http://www.ietf.org/rfc/rfc3501.txt" TARGET="_top">RFC 3501</A> * for details. * A client may want to "poll" the folder by occasionally calling the * {@link javax.mail.Folder#getMessageCount getMessageCount} or * {@link javax.mail.Folder#isOpen isOpen} methods * to solicit any such notifications. * * @author John Mani */ public class MessageCountEvent extends MailEvent { /** The messages were added to their folder */ public static final int ADDED = 1; /** The messages were removed from their folder */ public static final int REMOVED = 2; /** * The event type. * * @serial */ protected int type; /** * If true, this event is the result of an explicit * expunge by this client, and the messages in this * folder have been renumbered to account for this. * If false, this event is the result of an expunge * by external sources. * * @serial */ protected boolean removed; /** * The messages. */ transient protected Message[] msgs; private static final long serialVersionUID = -7447022340837897369L; /** * Constructor. * @param folder The containing folder * @param type The event type * @param removed If true, this event is the result of an explicit * expunge by this client, and the messages in this * folder have been renumbered to account for this. * If false, this event is the result of an expunge * by external sources. * * @param msgs The messages added/removed */ public MessageCountEvent(Folder folder, int type, boolean removed, Message[] msgs) { super(folder); this.type = type; this.removed = removed; this.msgs = msgs; } /** * Return the type of this event. * @return type */ public int getType() { return type; } /** * Indicates whether this event is the result of an explicit * expunge by this client, or due to an expunge from external * sources. If <code>true</code>, this event is due to an * explicit expunge and hence all remaining messages in this * folder have been renumbered. If <code>false</code>, this event * is due to an external expunge. <p> * * Note that this method is valid only if the type of this event * is <code>REMOVED</code> * * @return true if the message has been removed */ public boolean isRemoved() { return removed; } /** * Return the array of messages added or removed. * @return array of messages */ public Message[] getMessages() { return msgs; } /** * Invokes the appropriate MessageCountListener method. */ @Override public void dispatch(Object listener) { if (type == ADDED) ((MessageCountListener) listener).messagesAdded(this); else // REMOVED ((MessageCountListener) listener).messagesRemoved(this); } }